Illinois Institute
of Technology
Libraries
AT 315
Stewart, John L.
Design of highway suspension
bridge across the La Grasse
DESIGI
Of A Hig hway Suspension Bridge Across The La Grasse
River At Massena Center: St. Lawrence County; g. Y.
A THESIS
Presented By
John L. Stewart. Orville C. Badger.
To The
PRSSILEUT AETD FACULTY
Of
ARMOUR INSTITUTE OF TECHNOLOGY
For The Degree Of
BACHELOR OF SCIENCE LIT CIVIL MGIE3ERITTG
Having Completed The Prescribed
Course Of Study In
Civil EgGiESERnrG
1913
Approved:,
ILLINOIS INSTITUTE OF TECHNOLOG Y g^kJ ^ T7^
PAUL V. GALVIN LIBRARY ^fJ 42J CP ^6^T
S5 WEST "3RD STREET v^f m , W\ *^~^^
HICAGO. SL 60616 . (X~ <?• Jifn^?
S?35EISIQg BRIDGES.
Suspension Bridges may "be classed under two main heads :
( a ),' Those composed of a light platform suspended from
a cahle , the loads passing directly from the floor to
the cahle.
f "b ), Those consisting of a roadway supported "by a truss
which is hung from the cahle "by means of hangers.
Structures of the first class are called Unstiffened
Suspension Bridges. Because of their lack of rigidity,
structures of this type are limited to short spans and
light loads.
Structures of the second class are called Stiffened
Suspension Bridges. The applied loads ere taken up hy
means of the stiffening trusses and distributed to the cahles
"by means of hangers. Dae to the rigidity of the trusses
heavy concentrations or symmetrical loads are distributed
over the cahle approximately as a uniform load, so that it
does not vary greatly from its original shape. Stiffened
suspension bridges can he constructed rigid enough to ca*ry
railway and heavy city traffic.
Such men as Joseph Mayer;' Gustave Lindenthal; and
George S. Mftrison,' have from time to time puhlished articles
in yhe leading Engineering Magazines on"Suspension Bridges",
ana it is due to their efforts, that this type of triage
has come to he recognized as an economical structure for
long spans; 5 hoth for heavy railway traffic and light foot
traffic.
2
3US!
8 E 3 S I
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Over
GRASS
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MASS
At
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, Y.
The site of a Suspension Bridge over the La Grasse River
at Massena Center, IT. Y.
The La Grasse River is a tributary of the St. Lawrence
River and is navigable to a point about three miles above
the site of the bridge. The river also serves as a tail race
for the power plant of the St. Lawrence Power Co;
The War Department required a 35 foot clearance for a
distance of at least 250 feet at ordinary high water during
the season of navigation,' which is at about Elev. 160.00.
The design of the bridge provides a 45 foot clearance
for a distance of 250 feet in the middle of the channel.
This was deemed enough to take care of all emergencies
that might arise locally.
This bridge is designed for highway traffic.
The bridge consists of three spans; a central span between
towers of 400feet; n and two side spans of 100 feet each. The
central span is divided into 36 equal panels'; the end spans
into 9 equal panels',' all spans being suspended from two cables
The anchorage roadway of 40 feet on each end makes a total
length of 680 feet excluding grade approaches.
'
3
SUB4STRU CIUEE
The highest water level on record being at 183.5;' this
height was fixed as the top of the masonry piers. These piers
are the tower piers and they run down to Elev. 154.66.
The cable anchorages which also form the approaches are
built of concrete. The space between the two wings is not
built of solid concrete; but is left open and filled in
with earth and stones*
On the Horth side of the river; soundings revealed a
continuous bed of coarse sand and gravel. Onthe South side
a gravely hardpan was encountered.
SggERSTRUQTURE.
Each of the two cables is made up of 7 bridge cable strands
1 1/2 inches diam. each. Each strand has an ultimate
strength of 267800#; equivalent to a unit strength of a little
more than 200000# per, sq. in. Their modulus ^f elasticity
is about 20000,000. The main span cables are cradled to
a batter of about 1 5/32 inches per ft., and the plane of
the land span cables is coincident with that of th* corres
ponding main span cable. The versine of the main cables
center to oenter of towers is 38 feet at the assumed normal
temperature;' at which there is no stress in the stiffening
truss due to lyye load.
The main supporting columns are vertical and spaced 25
foot centers.. Each column or leg is anchored to the corres
ponding masonry pier with 2 l/ 2 inch steel rods embedded 8
feet in the masonry.
..
• '
4
The stiffening trusses are 16 feet on centers and are
8 foot yf — 2 inches deep; back to tavk of chord angles,
LOADING A IT D ST R.E SSES.
The estimated dead load was 780# per lin. ft. of "bridge";'
and a live load of 51#tper sq. , ft. floor area, (Class "C n
Specifications for Highway Bridges.), on a 14 foot roadway.
The eables,cable fastenings, etc., were designed for a
maximum uniform live load over the whole bridge at a
minimum temperature which was assumed at 40 deg. F. The
floor was designed for a load concentration equivalent to
a 15 ton road roller.
The limits of maximum stresses in the towers and anchorage
steel, including "bending stresses in the towers due to
temperature changes is about the same as that of a live and
dead in the trusses. The maximum unit stress in the
cables under the extreme lull load on the entire bridge at
minimum temperature is less than 49000# per sq. in. That
of the suspenders,' which are made of the same grade of
steel wire; is only 17000# per sq. in.
The estimated cost of this bridge complete is ahout 4E000.
Articles on the estimate and construction of a bridge for
this site appeared in the "Engineering Record" Oct. 5 and
Hov. E; 1912.
5
spECi Frcrrro i s ."
Coopers Specifications Class "C? will govern this design,
(1) The loading used in designing the floor sywtem was
according to Coopers Class "C" Spec* A 15 ton road roller
was also designed for*
(£) The live load to he used in designing the stiffening
trusses will he the uniform liveload for spans of 200 feet
or over'; as given by Cooper in his Spec, for Highway
Bridges*
(3) Temperature and wind stresses will he negleoted if
they? combined, amount to 30<% or leas', of the combined
dead and live load stresses in the ohord members. TSis
is according to Coopers.
(4) Steel for the cables will he according to the spec
ifications of John A. Robling's Son's Oov; Trenton S". J.*;
steelto have an ultimate strength of S50,C0C# per sg* in*
A factor of safety of 4 will be used.
(5) The floor of the bridge is to be of 5 inoh long leaf
yellow pine plank. Guard rails 4x6 inches are used*
. — 
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6
DESIGCT OF FLOOR SYSTEM.
The design of a floor system for all types of gri&gee
is practically the same, so no lengthy discussion will he
gone into in designing this floor system. It will "be
designed according to the "best modern practice,
THE STIFFECTIITG TRUSS
A three hinged stiffening truss will he designed, as
this type is much more satisfactory and has a greater
carrying capacity than two hinged trusses.
The trusses are placed 16 '0 1 'center to center and are
8 , ~g~l7 t g' ' deep, hack to hack of chord angles.
The stresses in tjre truss were determined according to
Johns on, Bryan and Turneaure's "Modern Framed Structures,'
Part 11". According to their theory, the cahle always
remains a parahola with its vertex at the center of the
span,' therefore the hanger stresses are uniform over the
entire span. There is no stress in the truss, due to the
dead load of the bridge .
The end trusses were designed on the assumption that
the cahle was a parahola. This assumption is not exactly
correct",' hut as it gives stresses that are on the side of
safety this method was used.
Temperature stresses were calculated according to
Eerriman and Jaeohys* "Higher Structure s"';' page 159.
Lateral stresses due to wind were calculated according
to Johnson ; Bryan and TuroeaureV "Modern Framed Structures,'
Part II" page 521.
All similiar members were made of the same section", as this
is considered "best practice in modern suspension "bridge
design.
7
SUSPE1DER ROM.
The suspender rods; 1 which transfer the loads from the
truss to the cables were designed in accordance with the
theory advanced in Johnson, Bryan and Turneaure T s "Modern
Framed Structures,? Part II.
DESIG1 OF OABIES.
After the trusses have heen designed and the dead and
live loads estimated,' we can then proceed with the design of
the cable. Specifications say that the cables must "be
designed for the maximum tension to which it will "be sub
jected. This condition occurs under full dead and live load.
Thevmaximum tension for one cable in this "bridge is
730,000#, thus a cable area of 14.6 sq.. in. is required.
Seven strands of 39 wires each 1 ; of ¥o.2 steel wire were used.
Clamps for connecting suspender, rods were designed
according to experience and precedent, they cannot be
mathematically designed. All suspender rods are fitted with
standard clevises*
There is a cable deflection which is due to temperature
and live load. The sag increased by temperature and live
load. In order to take care of this sag the maximum de
flection was determined, and in oftder that the bridge
would never drop below the horizontal, the trusses were
given a camber of about 5 feet.
THf cables were cradled as this gives a greater resistance
against lateral wind pressure.
8
DESIGN OF TOwERS .
The towers were designed according to Johnson, Bryan,
and Turaeaure T s "Modern Framed Structures'; 1 Tart II".
They were designed with three panels,' the top and
"bottom panels "being X braced^ and the middle panel thru
which the driveway passes is portal "braced.
For cable seating see detailed drawing.
GABLE ABCHORAGSS.
The function of the cable anchorage is to provide
weight enough to counter act the tension of the arables.
The bottom and side walls of the anchorage are built of
1:3: 5 concrete,' and the space between the side walls
is filled with stones and earth. Thus a cheap and
stable anchorage is obtained. See masonry drawing for
details of the anchorage.
LOADS .
Floor system — .232 Kips/lin. Ft. Cable.
Truss .200 n " " ■
Suspender Rods — .005 ■ " n ; "
live Load .480 ■•■■»■
Dead Load «««**.,— .jbg " " » "
Cable — — ~ .050 * n n »
Total 1.297 * " fr — *~~
.
Conn pu for ion5 for a
U~J.
Af*MOU/* //VST/TL/T~E: orTCCrt/S/OL.O&V
C/"C<4&0, /L.L.
./.
^ssurrte width be/ween Wringers . 29"
3 * ~~ M * ~~ 3 = /ooo* for ye/ low pine
c = ~ .*. d ' st viLfZl /A ssurrte roller distributes
we/phi over 2 plants each /z" wide. Then b=>24"
and d = \l 3xrsoo*33 =. 3,34" f^lanKing wilt be
' ?x/ooox2+ " " ,, / / 
3X/2 since the wesa/fT" of
rotter ts probably distributed over o /arger area
and Specifications art /3. state that f/oor
pIciriH. shall hay* a thickness jh /ttches at
least eaua/ to the distance a&arf of beams.
l/y<s/ahf of f/oor.
Weight of yellow pine 3.***joer ft. board measure
r/oor area m &ooa /+ ~ 3400*'
#440 X 3. SUT3  39200
\4/beeJ guarefs 6x«? ' Zona teat ye//o w Pine
600 XZ A3.? X.5*<*r =■ 3+00
Tot ut * &3ZOO r&tOO =» 36600*
or /t&o per pane/ .
2.
D£SI6/V OF STf?JMG£T/Z.
Q r ' 5H 'r
K
//./
**
7? f = 7? 3 =■ 3.75" K/'pz
J.L.M 3.7? X5.5SX/2  243.2 Kjt? )H.
D.L.M  ■4r' w * 20 per ft wesyfif of
str/naer » Z22 * + c/ead Joad of fJoor on str/rtger
//./A 33 'A 3 6  ^ 320 * Tbfa/ (V = &42
, „ _ 6V^A///A/^
s.o
K/f>
IH
ToJoJ M  2+92 + 90 =■ 2S&2 AT//? Jrr. =
2S&, 200
//*
3 * 13000 (art 4£ Sjoec^
M, . X = £££*££ = fSL9
5 C /360O
'rvt+t hand boofc — for a 9 U  ^s^ J 4>eaw
c
 20.4 .". Use for a// sJr/rryers 9" a) 25* per ff;
I beams.
DESIGN or rLOOfZBF^M.
I
* i
si
\
 v/./
/ //
to — & —
vaa
Concentrated load / 5 tons on two o*/es io'
centers • and upon the reniai m nq portion of the r/oo^
a load of /oo of f/oor.
K ~
> \
«6 «£5
s^>
%
%£>,'
/~o
^ ' "
K,
W = Sx//./ A IOZ>.+ X 32
VV Z  At' = 76+ L*Z£
W* ~ t./ X/OQ \3X <Qj 
Wf = XA /./A JOO A 3 32
 S. // AC .
== / 57 /t
 / 66 A. •
DESIGN Or ^LOO^BSr^JM (cortt)
Moments about ^ % t = A66x/ + S.//A j.s + /.s/a 6.s~ +s.// x
S.S +4/6 */3.<T i /6 = i2 ~ a  /O. &/ K.
Arfow. a hoof W 2 /o.Sf x 6.S  4/6x4 Max. L.L. Mo**r.
=» S3. S3. KjO.ft. m 642 240
£>./. morn, floured frort>f we/ohf or? r~/oorbeor+r.
/ floor bean* /& ' a) so ■ Boo
F/oor } yvheeJ auords  /790
defa/fe /o
<?<Z&o.$~
P.L Ma^r. =• JZl* * 44>ao*/6M/6 _ j/zjBG**
s <?
~7ofu/ Alow. =r 6422«lO+/f23ZO = Tf+tto"*
I_ _ £L  7S~+60O _
/fooo
J&
r~rorr? handfroo/C J. for a <?2* /S~" I beam
— 5~8.&
.'. Use tor a// f/oor beams /s'oO^z
per //. I £>eo*t*s,
We/orrf of /7oor sys/errr
■&600 oer t>a*?e/
■46
//■/
»/ .« <<sf>s oer //£ o/^
br/dje =z m ;z/ X/f>s jeer fA of truss.
MAX. END 5 tlZ:^ '/? ON r/QO^S^^M /Live /oaJ)
J
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/ a
/&—o
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—
<¥. A 
—
—
.* —
///
*«
/c
■ T' T
/ •/
1
Momerj/s aJjour 1  /? z
f?tX/6 = 3SXJ.5~t8JJX8.S~<3/x//.S * 3. // X /?: i?
K 
2Q3.2
/3J J</'&s wc?a . e/?c/ shear.
*.
f^ivefs ifi connect /on <^s fo fl. beams
jE^cJ shea a = /3,/oo VaJue of ^r fillet '* bectr/**}
it
~ pJ. ~ 67SO
/3IOO
6 7 'SO
= 2 ri ise rs
h
design or ^TrrFEMMG t/xuss^s.
>H ~,~>uryir>tior> ryiaJe /bar trusses w/ if riot be stressed
uhjcr dead loud . L.L. = SO w= 60 A /x J& =■ % 9& Kips per
fr. „ * brjdge  .48 */&$ per rruss .
V* ^L ■ *2*+2S. = 32 . Kips
6 6 1
Max. AW = J2f£
S3
Merr/man «* Jacohu. f^art Tg.
, 43 X 400X^00 = y+ So /c ip .f+ %
53 '
i?ec. & * /,2/
rbr a// dtaaona/s . ( mo/i* st>an\
A/ax. 5/iear  32 X/&s . £}<e5/ar?ina stress * /.2/X32. <
^/T:* A'f>3. j^or a// chords , /twain s&an\
LSes/anma ry7C>mer?t == /*?5~o K/&. ft
Lses/an of CAord ^ect/on.
for fen 5 /on a//oired stress = /2£oo
=*a
r or co*yf
if>ress/orr Ji? <* /zooo  £&
tCeao/red area for ¥&tis/o*7 — ££££  /■4.S'
C Sx'ZS
fry j2 ^s <s^6x^ area  /a. /a, !
><> r/\re/s /<4Z
/6. 76
v .: a*: .
DESIGN or 5TirrE'Klll\J& r/TU^S (con*)
ss/
" " J 3 "
/^or corytjpress/on — 5 =■ /2000 — ^p . r fo r 2 <c.s ex<SX ■—
 A82" / S:Sirx/2= 66.6* 3= /2000 ss '***■$ . =
/.82
joooo .*. ■ ^ =• /£./* read area .
8x joooO c
.'. f^or L/e>t?er and /ower chords ( ma/n st>an\
use Z Zs 6X6X~~.
J^/agor?aJs
lOesJarnr/a srress  37.5" x/ps. for ^errs/or/ read.
37.'*' a " T ' " " t " a"
area = — — = 3.oo /ry 2 Zs <9X3J<% area = 4>f
/or comr>re35/or? J = /oooo  **3*y <~ y \.
/ f
« /oooo "* *'***!+  * 3 oo* a " ^Irea rea'd = %£ =
/.2S < 5.&
a " / " " "
6.4f .: 0./< Use 2 Zs 4A3XZ for d/ayo/ra/s
(rvra/rr and errd s^>ar>J. For ertd d/agor/a/s 2 Zs
6~X3x jr **v// £>e used.
yerhca/s are used Jo rvaXe She urpsuj^aor^ed
Je/7pfri oS c bored Sryta/Zer. /Z z^xjg'x^'kY/// be
used.
s.
pes 1 6 is or STirrEsiii*4& truss ^o^t)
Chore/ Sec t 'ion (end spans)
Max. moment = ^L = ~x &s*20o*= 725 </b ft
S3 $3
For le»sior? = 72f a reod area . Try 2 Zs 6X6x~
8A12S
area = /o. tz
2 ri^eSs : 74
*"f 6 ^ , c ■ < 5S /
O.K. tor corn press /on  D  /2000 ■^~
= /2000  **.***■* = /oo+o ai read, area = '?££  so*"
.'. Use for both cUorc/s 2 sLs 6X6X^
Weight of Truss .
Chords. ^4LS bxex yf //. / a? 31 * **//./x 3/ = J37&.*
* // *
Uja<jona/s—z/5 +x3x% 9.74 a) //./ = 2x 2 X9.7+X//./ = 4324
Verticals— )jl zi*zfx~ a) ^.*s'^ 2X8***i = 66*
To fa/ we/p/?/ f>er f?ane/  /3Z6.^r*32.'9^sa + /o 0/0 for
detai/s * 206Z or 2.1 X/ps ~£ = /9 K/ ^ ^ £ ^
ft, of truss.
**
DESJ£J\I Or ST/rrErJV/r^G TfTUSS (co*Aj
/Tii/ets /n Try 55. ( zf r/fe+s\
•Phear «■ /oooo LJear/ng = /3000
5/nqle shear ~ *W3 dovb/e shear * 8836
/"or c/iagona/s  Stress * e.s x S78 =37.7 KJps (coyytp)
__^. a 5 rivets 23ear/ng on x ' o/aie ^73"o
for tens /on stress =• /2.SX6.06 * rsis x/ps. ^tjL
/3
J 2 r/wets. Pear in j on /g" pi. * //.^? ^/>e»5.
/^z" cnorcfs  /Far /ens/os? f/na/n spar?) stress =
/6.74x /2& = 209 X/ps 7?<h * /S rivets. r~br corn/?,
stress /s ' /8 x /oooo  /8/.a *:/ps j~ =» ;e r/ye+s
for ten s /on (end span) stress * S.<44>x/2.s = /03 /cips
g T 2 " '4 rivets re per/ red. F~or corn press /on stress
= /o.szx /a. 04 = so/.? /</ps ^f* /S n * e * s
f^or vert/ cats use & rt vers .
/o.
D£5J6M Or" 5T/r/=~£:U//V& TRL/S3 (coh/~.)
f = rov/3ion fc
v/3tori ror ex.
Ypartsjon
for a change of ± 70°/=\ from normo/ '. Elx/pomisjom
coeff/'c/errf for steel = .0000065"
L  e {J =• .000006S XTOX^OOX/Z = Z 2./S
,\ a"" w/ 1 / provide for fofaf ryiovetnenf ( 'was/? span)
for end span  /. = . 00000 &if x 70 x /oox /x ~ ±.545~
.'. ijf. wj // ' oro wde for +r?ov&tr?er}f
flinges.
find h/*?ges  £~rrd shear  /& Ar/^s for orre fruss.
f/i area  j§r ~ A 6 or a /jjr f/j?. x4 Zy p/rr mf/

he used
£er?fer A/nge  Ce/tfer shear = 6 s</i?s t>er fruss
/A7 area = jr s .6 or a / jP/rr. sd x^ J?'n m////
be used for a// &//is.
//.
£>£^/6fij Or S'T/Frf/V/MG TTFUSS . (com*)
~~fe ' ™/?^^/v'l&J2z±'€ s  s J&C \ _ ~7f^ f££'
O s Temjs>erafctf*& stress fJ?s. t?er so./ +7.
s =• saj rot to = . 09S~
e= coeff/c /er>/ of expa^s/or?  .00000 6S~ for /">T
f * fasr^e of re**?£?er'afc/y&  70 1 '/? fro^n /7or/*7o/.
£f= moc/o/c/s of e/asfc/'ry = 30,000^,000
d = det>Jh of y fuss = &o"
/ = /ertgrh of S£>a*7
J7__ (<?+2.4 X.O~ff6~J OOOOO 65 X70X 30,000 j OOO Jr 3
/C X.OSS X^fOO
£. 26fO
*tr&
/2.
5trd5~> in Choreas.
. v 7= bertd/^a mowenf due /a umtorryi w/wd Joad '.
p  L'n/fory*i n'/yid load per un/r /ena^k of f/ /J^e .
X = dsfu+rce *~o sec f /on a£ wh/cfi ,V7 /s des/r<sd .
h = d/sfa^ce from £ of ^ower /o £ of //./vs.
t * base fo /\/<j&er/ a n fou a rjtf >+is
M=,JL f /  g / g ( ''* )c 7 (Jo/txsom framed 5+rocf)
7J
where c' = f ( »+ H»± f 5Qq of cab/e
Jf = due fo w/*7<d /oacd // <due fo deacf fo&c/
Hr'
Zf " modo/c/3 of e/asf/c/Jy I = /+*&*** en f of ;*rerr/c<
of ~trc/5s.( I of chords ajyoo/ fross £\ xx.
I  (I c t ad )2 d**6.z I c = fo/ z £.s
^yror/fy = 2xjaoa
If*
6X6
k £ abour cerrfer of <
//■*■
C = A 0002*f
= 6&/^ & = /&/&
/ " 2 C&0./Z +■ 'S./8X &&z) — T77SO
3S [38*]
<?£> x &OO0OX7773O
SX.osf
= x oaooooO s97
/V &/■'// be footed for She &o/r?f of sncrx . /../.. M,
/3.
^<? C /^ ^" ^X ^y €» * .000 24 X "23.2,* &■&*■
= .//6/2 fog of / 3065
(e <C ~*) Jog e ** <?(/**) Jog e " .0002^ (36768)
(.43<?)  . 33237 Jog Of 2. +'64
(e c ) Jog e c => c/ /og /0 e * .00024* tsoo x,^? —
. 43336 Jog of 3./620
yy or P = 300 + 30 = 330 jrfrf: 39. ,5fex:'f/c.0f/0*r&
OOOOOOO S37
L /+ 3. i£ZO J
//#
000
Lot 1 era/ truss = /<z,'o" <Jaez>. cftorcf stress  —7
2SOOOO
d
^3poo,ooa „^^ *
— '— ' * J '6 0,0 00
/6 Jt /2 '
ita
Z8./8
 J 3 TOO
Jjtice rh/s stress eAceeds 300/0 of the of/owed
dead aid f re Jo ad stresses ff w/J/ J>e cotisjJerec/.
V
<=,
 c I C, e c~ <?' / John sot? , f3r~yo*7, Tur/ieocre
/4.
/
330
C, ~/T f=~Z 7 =" //0 , 5~OO t OOO <£, = 3. JS2 X
% OooooaoS37 * J
//O t SO 0,000 =" 3&9 } <?0/ } 00
y= — .0002*? [ //o f S<TD,#VO  J^Sj^o/oool  T o~7S~SO
f=~ J / ^ 4TTST&0 „ a"
/or a/aqo//a/s area reaa. = — = 3.2
J I /Sooo
Try 2 Z5 4X*9x^ area = 3.7f
/ r/iser ,44 _ „
cr j 1 ' / " » „ 3.3/ ° 0<
/or fate rats use ^.jr*x£ froth t+ra/*7 ana/ e /id 5 pais.
tj *'ye/s /t* fateraJs.
S/Pr^/e shear s 44js cq/i J?e /*rcreasea / fa crfo
r4rt S3 ^j&ec/f/car/o/rs 3t,
 3 nrets
7jt?ec/r/caf/o/*s Csfress* 1 3.3/ x 'Sooo  sssoo
SSSOO
a
fledes/fti of ^/tor^s for Truss .
cf/ord area /wcsf J>e /Mcreasect oto accooif of w//7d /
ar/d fern^eratore stresses. The a //o wed wf stress car/
pe wcreased Jyy sotfo whe/i mva' ar>c/ temperature
Stresses are covs/cfereaf. /sooo +3o*/o = za*?oo w/tt
be oftotveat far the c/^/f stress t?er so. //f
/£■
D£S/GN Or LATERAL. SYSTEM (co»*)
\A//r>d stress = 2S0000 L. L. =• /a/25'o
*
//
Tern&e ro fure sfress = £690
4 re* for chords = * SP** *'"*«*  20.3 « "
23+0026+0
, " " " «
Try 2 as 8x6x~a~  22 9s a
2J. 2 a .: O.K.
/or end smarts— Sxexlr" xls Witt he used.
/( / rets in Chord
Ofress = 2A2 x 207*0 = 4.^0000
0ear/rt& or? ■£ t?/are of /3000  7/3/2
4*40000 _^ / v
= 37 rivers (/na/r? span)
1/3/2
find spar? — vS~ = /2.62 x /2S~oo  /s7SO(
/S7SOO
6 7 SO
= ;?<*• rivets
/€.
DE5I6N OF AUSTEN PER RODS.
Where the distance between cah/es and
floor he cms /s short stee/ roc/3 \a//'// he used as
suspend&rs . ^i r a// other po/nrs suspenders
cons/sf of h/gh strength steet rope strands .
f^ hanger pu/f per J/n.fh H = hor/zonta/
component ot cah/e stress, /= /er/afh h 
center ctef/ectton of cab/e s » j
r= *3Lj**p± =, .S3 «'PS per /'*> &
ZOO * ' '
/ per panet ** //.j#.88* 3.7r *csps F* per hanger
= "Z38 *'ps s4rea rega. =» —= % so$
Use ^r <p rods area  .S068 °
Longest rod about 44 ' Zona . We/ghf = /.0+3 x
9<> = 48 per ferret = 94* jf^ » 3.65 per ft: of truss
(majc.) Assume 5~ per hn. ft of truss for n/e/ohf
of hangers a net c/e fa//s . f^r cah/e we/ghf
assume 5~0 per //n. ff.
/7.
PESIG/V OF CA&lES.
Total Load on Cable.
r~~/oor system = .,2^^ Kips / ft of cob/e.
Truss
<*D uspender rods
/_/ve load
Wind load
Cabfe
.20 "
= .00s "
.48
 .33
= \o*_
7b+a/ /.297 Kips / ft. of cabfe
7~= max . tens /on in cah/e . ti  horizontal corn/?.
of 77 /= span . h  cabJe sag at center, s = t~
/
w/
T~ s jr V/+/6S*  fi \f/*/6s* Aferrsrna*? * UacoJsy.
( 7=2i *■ fur.)
ft* **9tx+oo_ ^ 683  r s 6Q3 fr~J^* =
3JC.095~ '
683 X /.or — 730 Kips. LJ/f/mafe strength of cabfe
■it a "
Wire «• 200000 rhetor of safety « ? WorKtng
strenyfn = Sb.ooo*" sd reo read. = ^^§g f '**
£/5"<? 7 strands of 33 wires each of A/0.2
steef wire. /rom 7?oeb/mg s w/re cata/o^ue
/a.
<a
DESIGN Or CA3L.E5. (conh.)
re a of fto. 2 yv/re = .0&43 7x33 = 273 w/res
a" ^
,OS~43 X 273  J*fr3 .'• O.K.
CsracJJing of Uab/e .
b* /are rat crad/ina of cab/e . h * saj as assumed
in o vert tea/ p/one. dh = decrease //1 saa due to
crad l/ny . dh ~ ^  f/?h* =■ 33  J 33* 4* = . 2/ '
b= <4o 7~/j/s chaise //■? sag J nc reuses the oab/e
tehs/o>? a&out ./ of / rfo. fierr/mai i daco&y.
( 7=brrttz.)
CabJe £2e/ : /e cftor)s. (Loads a*?d tetrrp.)
C= length of ca b/e c= t (/t^s* ~ s% A
 too // f jx.afs  ^x.ogfs )  407. 3S2. ' kef ween
to wers . f^or ^em&er&tL/re — ~ ^ ~ =
3 X .0000072. X 7(2 X 4073&JL . ^^ '
/6X.O&S
/=br //>*? toads  \dt> = £^ dc= ^ // 3 3 >)
T dve to J/ve toad 0»/y . //= £^ = f****? m
** 8 ^ ~&xp9S~
25~3 K/'pS / = /.07 /7 ' /.07JX2S~3 =2 7/ /</pS.
_^^_____ _?■
OFS/6A/ Of* 6^&Liz5 (co**:)
Jc _ *_y&22Y,A.« J 5S?) ./##' ^ £ri^ . 3 _, 7 '
/+.& *30000 K ^ y /6A.035
Aierr/ryiar> t, ^Jacoby . (T^rt jjz.)
7~o/ot/ deflecrjon » .405 +.36? — .772
J bis is pro is j dec/ by comber ma trusses. 7~bey
wtlJ be cambered to a rac/;c/s of 6os/ or about
74 /„ 60 o .
zo.
D£SI6Asl O/^ TOWZr/^S.
r= /I [, +( +*»«, r *£)*]*
= /29.7*X /.«?/  /33 K/&S
" X /33 =» /*?■ K/f>S // • fO X S3 3 =r £2 K/PS
,,,.3
/,/.&
K/ps
* 730 =■ 1/3 KS/?S
*8
* SFS'4' K/£?S
V* »  02/36 *■ „?/^ Az^ir
& ear //>,<? s^rea fo r fos/s .
s4//owed beanng or, masonry  ^oo
^rea reyc/ . = —£■ = S+f a s4 p/a/e +& x*i " w/'/J
be usee/, ^ rea * /aoe a .; <?. /C
/Lena// ? of C7ab/e .
A^V>7 Sf?art  «?07.332 /l rt<J 5/3MS  £_ = ?,(, + &S*+ fow,
■y
L = /oo ( / + £ x.si^h £) = //6,s To/a/ /er/gJh = *?az3&
T2x //e.S = 6^o.3s' £~y*/jre /er?^/h w/// be a boo/
6TS
2/.
J 3endmg /foment in ~7~o we/5.
A/ s Q/+ \/d Johnson , J3ryan, ~T<jrneaure . far / XT.
O' load with V caus/no a def/ect/on d
]/ = vert tea I load / height of tower
3 H A */
^ ~ 7? "Wt ^ ' ^ or J' Y e }°°d (rna/r> s/?ar?.J
£ * /r?odi//c/$ of e/ast/c/fy J~ hio/ne r?r of tru^s
(end s&an^ Q 
Va>c
r=j, J for tower.
= +9+30 fl* *L = *pm_ =
&S 3 X.09S
I = (33. 32 + 11.5 x *&32 *J 2
J „ S X 2fO x(/2.fx/2)x /OOX/2 11 ^^° K 'f s
/? X 30 , OOO x <?9430
2/3
C r
30 000 X4BOO
_ 2/3 X 2,OZ X PO/2B
G*
 .00000/5/ c = .00/2.3
 / /s~i K/'/os
/.<*2&  ,96~S
ran c/ = 5Z3X.OO/2 3X6SX/2 =■ ss a +01 ct = /. **a
ct = , 00/2 3 X 6&X/Z = ,959
/V * A/ffX 44"JC /jg + 2/3 x 2.02 = /3*o *'/? /n.
Z^e5/c/x7 of fosh
Y
TT
J
^ s4 SS c/ m ed S ec tion :
" " 7 "
<?—>
//
2 fr/s. 22 x #
J *'/*?* **■*&'
= 2+,75
= 2/00
Y
Tote?/ * 5"Z27
22<
D£S/GA/ OF TOWF/T5.
— j . *
/ a boo £ xx OJfS/S  I, = J~X 22 A JL + 29:7S~X /2.2a =
/6
29/0
3 A
To fa/  2S/Q +f04i /397 = <4S//
u+
/39T
r * V. SZ27 *''*
. 3
I about yY axs/'s  I, = It* %■* 2Z = 5 '°°
J, = Jxz+xHZ + 2J * j^l* = /OfO I 3 =4(3.26+2,38 X 3~&*)
* U fb  3S3
■v ■*
Toha/  5~oo + ;o5~o r 3*~3  2<4o3
6200
&a
>y  V 7TT7 m *»+ a
— = r=~ = i 3 ^°. = 2,/e ~3ec//oA7 yHodu/us rego/red.
C 5 62 <
?*iL = 386 = J. usee/. .: O.K.
J 2.43 7 C
5/
B>
' r^sses ^jn_ f[ £JV£f_ J ~>r&cmQj
v> /4rf.<?o. ^pec/f/'caforts ~ /a/era/
j arejjsure = /oo t?er i/erf/ca/ fr.
■f O d  "S~0 +■ /c/fera/ con*/?, of
\ cab/e stress due /o crad/sucf s=
//S~0 +■ 730 COS <¥ =■ //3V '*■ /4600  / S7i>~0
5_^_ Cc =* //S~0 +2300 = 3*5~0
yA <J  //5~0 + 2300 + '800 ■*■ 65~0 = &900
34? f<?A<?5 reacf/or? of $f /ff &{?'"$ \ /russet.
23.
DE5J6/V Or TOWFffS.
H //
for £)ct try 4jJs 3x2£xjg w/th /c?c/r?cf t?etweer?
5;
/<.
r» 2.26
fcrc/r?a
stooo Z°l / =
r
23 ~ =282
S = ,6000  ***3§±  7260
■*fa
4
re a re*
><&.  '¥& 
7260
s4 rea (/sect
■ 6 S2
.: or. for £c
use same
w?
— sect/or?, for ^4a 445 sx3r^~ Z5
// be c^ect 22 t>acX to bocK of z.'s.
'$***■■
**^~~1
r* 25Z
•^ * ?6000  — * &/6Q
ita
Cd= Oc  5/
s4rea re<sct.    ,^?5* .'. cl/<,
res 5 = //5<2 sec o = //so a: /. 3? = /fso
j*4b  a 3  3 tress  S2&o sec e, * s*s~ox /./2 = S88o
' J ' " *r "
ror these members use 2 4s s*3* —
/6
>4rea read. =
S880 _
/6COO
36 7
: <a/r.
K^H
L ?e"/?c//*7cy t£L2l*2i 0/n &b >
V^
^
/
/f react /or? of trass
for ryro/r7 s/?an — /X —
**g£o=^ s ^. for er,o\spor, t?~ *%£+= '«*«
*&oo
24,
DESIGN OF TOWERS
Morn. • 3.5 X 29 tOL 5 re/'/? ft = t, 220,000
//*•
Jject'/ort modu/us react.  {,2,20,000 __ ^^ 7^ ^
' /So 00
ofs. 24x g , 4 2L5 3X 2£r x jg . >4rea  /<? y^.sve =24*2
r "i
•* — ^4~ —
L J
I about hor/zon+a/ axs/s,
J for ph. =■ & * ■§• * **■ x 2 = ^^
I ror Z.S =4(/.<?2 +■ /.63 X //.07)~ 802
Section n?odu/u^ =• — =■ /3g , ; O.K.
L.ac/*7g used between Z.5 .
f3rac/rta //? Sc be C^o repress /art or tens /or? /n
brace = 5£' /=?*,' too ."s4rcA. Ena". = i+2L**3 m
■#■ / / ' " " S~ " a"
£000 (dse Z ^.5 <4X3Xj£ area  4/& r~ /.*•? .
Z?  /6000  7Q x 4.3S x /2 m /2.730 ^T = &?■ area
 JJ? fZ730
read C/se tb/s sect/on for o// braces.
/T'fvers  Pd and Cc  7 I^SJf±£?  //
"~— " 44fa
s4ct _*"°*»'++ m 2f 4b and Cd = 't>ooox«S2 _, /g
44/ & 42 2 S /
os ^§ = r e ra c,„ 9 ;„ 0c» c  /6 %tT' 3 
/6 44 J 8  t/a/ue /*? &/tiq/e sheor.
■4225' = beor/*f<p or> — pj '.
DA/ £
/f/J
C£A/
/&/3.
7^/?WW^^
%oo
■ o
^^m^ 7 ^
L
^x —
>• 4& o
> AJ "T Jan. 2Q, 13/3,
^ fo O +*
THESi:
^L^L^k^
~ 2S8 JZf^r. fnfersecrson o/
SUSP£N5/0/\/ Br=UO&£
LA 6r/?A55E /f/Xf/T
X 7
£r Ord/rarr 5 rape of ftii/er /oO.O
frbd/cj o £ Camber of Spar? s af /Vecro 7e/77/i <  (,08/ /o 3orrom C/iord.
C/ /Sf.6b
AIT Jan. £8, 1313.
33 W/r^z
><? •••••*•
••••• t
• ••••• •
AJX ,4pr,/ /^ /9/3 )
J
p
K
!
THEei
OV£f?
La
A7a3
AffMOO'te
y<r+ « A $Z<LU5^f. £2^ck&!^ ^. t&tz^f&Z'r^
//V.5 T/ TO' T£
6r f?A 55£ r?/ I/Fft
SEA/ A C£NT£R,MY
or T^CHA/otoar
Hfil.r ifvrnn i IS/env. ' Afa/Lr J^cr/c/v AA
£/. f VA r/0f er 7b W£f? /^/£j^.
a'a
3>
3'6'M
. =i Ji,
9 ' o 
f/7e t^e/'f/fr 1 of fthe , £7/7CS?e>si?ye sw&sjt' At/ive &
/rt //?e ca£/e /c/~ tf s/^/0 of eges// fosses*??.
7" /SSo.ooo*' I hST fftg'd — 3 360, OOO*
i*/e/<?Af of coster*/* =■ 'fJV " ^?er Cf. /*>? = ^e>^c"^er c~^ ftt.
3,36O,ooOl*t0£>0= &d& Cts. ycf$ /?e#c;/s0<f. per Ct4S*.
^s/Zmored vo/tssw e\cf rlicfiaro oe •= /POO Co yds
f^LA/V Pr~ Tew^S? f^/^rT
J
/ »
'"* »
n
8 L 0
—
a
,1
o 7
J
■?
\ '
I
CONCftETF
0i~
m
I;
W
\
'•",
NT
■ii
V»
■1 '
At
I,
>M;V
»;
*■'■'"■' ; j.. •:" ■ * '.■.'■■'... ■■.■ ; '
t
1
~«_
TH
PA/ J3
'^/O/V sJO/A
W*43
A/ L OWFK
o/^ 7> =
Chord C?p// {
2 * '
ach chord
THE3D!
suspensions/ bridge over l4 ^ff^)55f
xj FfMOISf? INSTITUTE OE 7~E£f/A/Oi06V
j &f%*. ibL *fli**sasd.
C?l*l^G
I
«G©G0 OOGO
M^/N SfsdM
30 X 9^X £
/3 faiy /ea/ ye? //oh P'le £>/ctnH
/3 /J"iy 'ear ye* //on £>'*7e f/a**rT 2x> se&orofdkr,
■23X/&5*£
 • • • • •'* • • • • 4
• • • •• •• •• •+
' ' 1 ' 1
1 !.....*{
Chord 5p/>ce (**?arn soar?)
//>/37Jta"x^. S3f>/'~ctt //7
*?aerh chord.
W/r>0 Anchorag e
£^nd f! be urn
■9 — & i
2£ s ex 6xJ
£/. '$8 3o
2£.S 4X j„
— ?
r" W/*
/2 /« rrlasOr"
1
5 ho re end / '/
Or Tress
6*4xj 4.
4" Vio/es for £
:A///V^ JffU&SFS sQ/dO Z^tLOO/^
'.
5T
g
'4
».,
r
~T
J f and T russ /^ocKer ^ rrn _
N — ft 3~S* B* + "
5cv/e 4". /'
both
p
1
t ;
^}
•#
Truss /r'ou.Aer _ ^Jr.
c/f Mc/frt Tower
/O tver end
Chord 5o//ce ( end s/roisj
£>/. S~7A #'*7 ■ * S/dtee tr?
each chord
y ^ho/es to* #■ 6&/r$
.V* stored f" JoiylivJuty
m m